That person turned out to be Marlin. "All through high school I studied bees and ants," he said, "and when I came to college, the Illinois Natural History Survey hired me to help collect insects around the state.
"In my senior year I was asked to collect bees at Carlinville to try to duplicate as much as possible Robertson's efforts. I spent two seasons collecting on 24 plants that Robertson had collected on."
One of the plants Marlin studied was Claytonia virginica, commonly known as 'spring beauty.' "We were very interested in Claytonia virginica because it is the plant in the network currently visited by the greatest diversity of bees," Knight said.
"Marlin's dataset gave us visitation rate, a quantitative measure of pollination we otherwise wouldn't have had. Comparing the visitation rates we measured to Marlin's, we discovered that the bees were making fewer trips to the flowers than they had in the 1970s.
"Marlin counted 0.59 bee arrivals per minute and we counted 0.14 arrivals. So even those some interactions are still present, they're weaker.
Both Robertson and Marlin had collected their bees, pinned them, and deposited them in the Illinois Natural History Survey, often still fuzzy with pollen.
To assess how much usable pollen the bees had carried, Burkle and Knight picked six bee species that frequently visited Claytonia virginica, two named by Robertson, and washed Robertson's archival specimens of those bees, Marlin's specimens and their own.
"We gave the bee a gentle bath and washed its pollen off onto a microscope slide and then we fluffed it back up with a hair dryer," Knight says.
Since these were all the same species of bee caught off the same flower, the default assumption was that they'd be covered in much the same pollen.
Not so. It turned out that these be
|Contact: Diana Lutz|
Washington University in St. Louis